RUI: Cosmic Microwave Background Anisotropy Observations

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The cosmic microwave background radiation (CBR) comes to us from further away than any other astronomical signals. Hence it carries unique information about the Universe early in its history and on the largest scale. In particular, the angular distribution of the CBR can tell us about the origin and early evolution of large structures in the Universe, such as galaxies, clusters, and superclusters. Hence many efforts have been made to detect angular variations or anisotropies in the CBR. Except on the 180 degree (dipole) scale, none have succeeded. This research continues the search for CBR anisotropies on three different angular scales, between 10 and 40 arc seconds, between 2 and 10 degrees, and between 10 and 180 degrees. Three separate techniques are used to achieve sensitivities some three times greater than previous measurements. The CBR also provides a way to reveal and map the density and temperature of intergalactic plasma in clusters of galaxies (the Sunyaev-Zeldovich effect); this measurement may be combined with X-ray maps to help determine the distance scale of the Universe.